Where did the Earth come from? This is an important question. A question that helps us understand our own origin as a race of sentient, thinking beings. Did the Earth always exist? Has our planet spent eternity orbiting the Sun, quietly unchanging? Has the Earth always looked like it does today, with the same mountains, streams, lakes, forests, and oceans? Or does the Earth change over time? Was the Earth always a planet, or was it built or constructed at some point in the past? If it was built, what forces caused its creation, and from where did the materials to build it come?

These are difficult questions to answer. The Earth is our home world. Before the Earth existed, there were no people. This means that there was no one around to witness its creation. At least not any humans. However, scientists, like geographers, are able to make educated guesses about how the Earth came to be. These guesses are called theories. A theory is a guess based on evidence. These guesses are made by scientists who study clues to understand new things about the world and universe around us.